Any of them should have varied perch sizes. "Natural wood" perches usually vary along their length. Wooden dowel type perches generally don't vary, but you can provide multiple sizes. You might consider a "rope" perch as well. Our birds also spend time perching on top of their cages. It's smaller than recommended, but that doesn't seem to bother them.

For small Pyrrhura conures, you might use perches from 1.3 to 2.5 cm in diameter (1/2 to 1 inch), though I might not go over 1.9 cm (3/4") for the smaller Pyrrhura (e.g., painted or green-cheek). For a Sun conure, maybe 1.9 to 2.5 cm in diameter (3/4 to 1 inch), and for a Patagonian, maybe up to 3.5cm (1 3/8 inches).